Interpretive Summary: Schizachyrium scoparium (Michx.) Nash, commonly known as little bluestem is a perennial, bunchgrass indigenous to North American prairies and open woodlands from southern Canada to northern Mexico. Little bluestem is adapted to dry, shallow, poorly developed soils where it may comprise up to 90% of the vegetation base. A scientist at the Southern Plains Range Research Station, USDA-ARS, Woodward, Oklahoma studied the variation in traits that contribute to canopy morphology within and among little bluestem parental lines, an hybrid plant population, and seven populations selected for canopy morphology. Parental lines expressed considerable variation for frequencies of discrete morphological traits and for means and standard deviations of continuous morphological traits. The seven selected populations were fixed for several discrete variables including growth form, lack of lodging, and little or no leaf rust. To fully exploit the genetic variability of little bluestem it would be necessary to obtain ecotypes from throughout its natural range and breed and select for new genetic variation that could be captured through recurrent selection. Little bluestem, by virtue of its outcrossing, is an ideal species for breeding new cultivars for pasture and rangeland renovation, roadside revegetation, wildlife habitat, and recreation areas.

Technical Abstract:
Little bluestem, Schizachyrium scoparium (Michx.) Nash, is a native grass that has been shown to have high level of genetic variation for traits such as; biomass yield, disease resistance, plant height, leafiness, maturity, seed yield, and seed yield components. If high levels of genetic variation exist for these traits, it is likely that it would exist for other traits as well. Thus, the objectives of this research were to describe the variation in traits that contribute to canopy morphology within and among little bluestem parental lines, an F1 plant population, and seven populations selected for canopy morphology. Plants were classified as not upright (NU), upright compact (UC), or upright open (UO) on the basis of their shape. As was expected, all parental lines expressed considerable variation for frequencies of discrete morphological traits and for means and standard deviations of continuous morphological traits. The F1 plant population was characterized by 12.2% NU plants, 22.4% UC plants, and 65.4% UO plants. The seven selected populations were fixed for several discrete variables including growth form (NU, UC, or UO plants), lack of lodging, and little or no leaf rust. To fully exploit the genetic variability of little bluestem it would be necessary to obtain ecotypes from throughout its natural range and breed and select for new genetic variation that could be captured through recurrent selection. Little bluestem, by virtue of its outcrossing, is an ideal species for breeding new cultivars for pasture and rangeland renovation, roadside revegetation, wildlife habitat, and recreation areas.